Down the toilet: Study compares pot, meth, cocaine found in sewage across Canada

What you flush down the toilet says a lot about you, at least to Statistics Canada.

The agency released results Monday from a year-long sewage study in five major cities, including Vancouver, where it tested the wastewater for various drugs. It began in March 2018 and ran until the spring of 2019.

Meth use was highest in Vancouver and Edmonton, the results suggest, while cannabis use was highest in Montreal and Halifax.

The average methamphetamine load across all five cities was 270 grams per million people per week, but the average in Vancouver and Edmonton was 3.7 times higher than the next cities, Montreal and Toronto.

Despite B.C.’s reputation as the most cannabis-friendly province, Vancouver had the second-lowest consumed amount of THC, the psychoactive ingredient in cannabis.

Researchers measured the amount of pot in the cities’ wastewater using a compound produced by the body when cannabis is consumed.

The average weekly load in Vancouver was 313 grams per million people, compared to 936 grams in Halifax and 833 grams in Montreal. Toronto was similar to Vancouver, at 327 grams, while Edmonton lagged behind with 244 grams.

Despite recreational cannabis becoming legal in October 2018, the study found no spike of the substance in sewage that month. The highest amounts were recorded in May and June 2018, with a smaller uptick in December.

Cocaine use was fairly steady across the five cities, with Edmonton coming in the lowest at 268 grams per million people per week while Vancouver came in on top at 425 grams.